322 



EARTH FEATURES AND THEIR MEANING 



As an introduction to the study of the ice-blocked lakes of North 

 America, and to set forth as clearly as may be the fundamental 

 principles upon which such lakes are dependent, we shall consider 

 in some detail the late glacial history of certain of the Scottish 



glens, since their area is so small 

 and the relief so strong that rela- 

 tionships are more easily seen ; it 

 is, so to speak, a pocket edition 

 of the history of the more ex- 

 tended glacial lakes. 



The "parallel roads " of the 

 Scottish glens. In a number 

 of neighboring glens within the 

 southern highlands of ^Scotland 

 there are found faint terraces upon the glen walls which under the 

 name of the " parallel roads " (Fig. 349) have offered a vexed 

 problem to scientists. Of the many scientists who long attempted 

 to explain them, though in vain, was Charles Darwin, the father 

 of modern evolution. He offered it as his view that the " roads " 



TIG. 349. The "parallel roads" of 

 Glen Roy in the southern highlands 

 of Scotland (after Jamieson). 



FIG. 350. Map of Glen Roy and neighboring valleys of the Scottish highlands with 

 the so-called "roads" entered in heavy lines. Glens Roy, Glaster, and Spean 

 have three "roads," two "roads," and one "road," respectively (after Jamieson). 



were beaches formed at a time when the sea entered the glens 

 and stood at these levels. When, however, Jamieson's studies 

 had discovered their true history, Darwin, with a frankness -char- 

 acteristic of some of the greatest scientists, admitted how far astray 



